Qi Peng
November 16, 2005
Biology 112
Literature Analysis Paper
In the past decades, the study of aquatic food cycle relationships had tremendous
impact on the overall field of ecology, contributed many important data that redefined
various ecological concepts, and provided us with many important principles. Among
these studies, an early paper published by Raymond Lindeman (1942) is especially
important because of its introduction of trophic-dynamic viewpoint on the community
concept. Years after the publication, the concepts explained in Lindeman’s paper are still
widely used by researchers to clarify their points and support their findings.
“The trophic dynamic aspect of Ecology” was published by Lindeman in 1942,
and the whole paper could be divided into two parts. In the first part, Lindeman defined
certain concepts regarding trophic dynamics, and made some generalizations of
productivity and biological efficiencies regarding aquatic systems. In the second part,
Lindeman attempted to explain the succession in a lake system and the trophic-dynamics
of this succession process through the concepts and generalizations he introduced in the
first part.
Major viewpoints guiding synecological thoughts at the time were: 1) the static
species-distributional viewpoint; 2) the dynamic species-distributional viewpoint; 3) the
tropic dynamic viewpoint (Lindeman 1942). While either species-distributional
viewpoint draw clears lines between different plant and animal groups within a
community, the trophic dynamic viewpoint adopted in Lindeman’s paper emphasizes the
relationship of trophic or “energy availing” relationships within the community unit to
the process of succession (Lindeman 1942). Through analysis of these relationships,
Lindeman concluded that a biotic community can not be clearly differentiated from its
abiotic environment, so he defines the ecosystem as “composed of physical-chemicalbiological processes active within a space time unit of any magnitude” (Lindeman 1942) ,
in other words, the biotic communities plus their abiotic environment. Within this system,
Lindeman further groups organisms into several trophic levels such as producer and
primary consumer, with each successively dependent upon the preceding level as a
source of energy. (lindeman) Generally, the more remote an organism is from the initial
source of energy, the more efficient it is in using its food supply, but the percentage loss
of energy due to respiration is also greater. (Lindeman)
With above generalizations, Lindeman then analyzed the trophic dynamics in
Hydrarch Succession. He noted that this dynamic process involves the change in species
composition, and productivities. (Lindeman) Specifically, in the case of Lake
Entrophication, the total productivity increases exponentially before the lake reaches a
Eutrophic level. But once reaching a eutrophic state, both the productivity level and
organism biomass of the lake decrease. Lindeman explained this paradox by emphasizing
the oxygen supply of the lake. As many highly productive organisms rapidly consume
dissolved oxygen of the lake in eutrophic state, oxygen supply diminishes and causes
those highly productive organisms to die out. In their place, many organisms that are
tolerant of anaerobic conditions take over the lake. Because these organisms take
advantage of reduction instead of oxidation, their productivity is considerably lower than
their aerobic counterparts. (Lindeman) Therefore, oxygen supply becomes the
determining factor in productivity and species composition of a lake.
As mentioned by Lindeman, the validity of this interpretation in a more universal
scale was still uncertain at that time. (1942) Researchers such as Hutchinson challenged
this interpretation by stating that only lakes already well-supplied with nutrients can have
a true eutrophication process. Therefore, other factors such as the nutrient supply and the
morphometric character of the lake all play an important part in hydrarch succession
(Huchinson 1961). Among the needed nutrients, Tilman noted in his experiment that
phosphorus and nitrogen are especially important factors. ( Tilman, 1976) Recent study
of lake systems hint that Hydrarch Succession is influenced by many different factors, not
only by oxygen supply and nutrient supply, but also by the temperature, weather, age of
the lake, types of organisms living in the lake and the depth of the lake etc. Even similar
lakes with only a few points of difference could have totally different productivity curve
and future species composition in the long run. (Meckler, 2004) It certainly would be
helpful for future trophic study to generalize a principle composed with all above factors,
so researchers could use computer generated model to predict the species composition
and productivity of each trophic level in the future.
Another important concept of Lindeman’s paper that was used by researchers
frequently is the relationship of number among producers and all levels of consumers.
According to Lindeman, the animals at the base of a food chain are more abundant while
those towards the end become progressively fewer in number. (Lindeman) This is caused
by increasing energy loss towards the end of food chain and the progressively increasing
size of the predator on top of the food chain. (Lindeman) This interpretation implies an
important aspect of trophic-dynamics in both lacustrine and terrestrial cycles: the ratio of
predators is very dependent on prey. Prey can limit predator population because excess
predators with limited prey population increase competition thus eliminate excess
predators. Therefore, in the case of simply one predator vs. one prey situation, there is
always a set ratio between the two populations, and the ratio is determined mostly by
factors such as the available resources of the prey. (Elton, 1927) This relationship is
termed “bottom up”, or Eltonian pyramid of numbers. (Arditi, 1989) this relationship
suggests that the biomass of organisms at any trophic level is a function of the
productivity of their resource base. (Mathew et al 1997) Two predictions emerge from
this approach : that more productive ecosystems will have more trophic levels, and that
the biomass of organisms at all trophic levels will increase with the basal productivity of
the ecosystem. (Mcqueen et al, 1986) These arguments provide an intuitive intepretation,
but they are at odds with the predictions of the simplest mathematical formulations of
predator-prey interactions that include any dynamic feedback from consumers to their
resources. (Mathew et al 1997) Alternatively, other researchers such as Hairston argued
for another approach that focuses on how the number of trophic levels in a system
influences partitioning of biomass among all the trophic levels, which is termed “top
down” ( Hairston 1960) Based on a dualistic assumption that a given trophic level is
regulated either by resource competition or by predation, “top down” approach suggests
that the number of trophic levels functioning in an ecosystem determines its trophic
structure. (Hairston 1960) For example, plants are expected to dominate in ecosystems
with odd numbers of trophic levels, whereas herbivores will dominate in ecosystems with
an even number of levels. Recently, through data taken from experiments on Lake
Eutrophication, researchers used the same fundamental approach as “top down” to argue
that the abundance of secondary carnivores accounts for much of the variation in plant
and herbivore biomass in lakes that is not explained by nutrient levels. (Carpenter et al
1984) [Long paragraph?]
Although these two contrasting views (bottom-up vs. top-down) are very different
from each other in terms of their methods and their predictions on the patterns of
variation in biomass at adjacent trophic levels, recent experiment data seem to lend
support for both perspectives. A bottom-up approach argues that all trophic levels should
increase with productivity. Numerous studies in aquatic systems and some evidence in
terrestrial systems show patterns of positive covariation between plant and herbivore
biomass, supporting the "bottom-up" perspective. In contrast, much experimental
evidence for trophic cascades in enclosure and biomanipulation studies in aquatic
systems, and an increasing number of similar studies in terrestrial systems, argues for the
"top-down" perspective. (Mathew et al, 1997) Therefore, it seems these two approaches
might not be mutually exclusive of each other. In certain areas, a bottom-up approach
works more strongly, in other areas, a top-down approach works more strongly. Instead
of two theories going to the opposite direction, most researchers today view bottom-up
approach and top down approach as two ways of trophic structuring emphasizing
different aspects of trophic-dynamics. Bottom-up approach emphasized on the horizontal
factors of a trophic structure, specifically in which multiple species at the same trophic
level compete for resources and share predators. (Mathew et al 1997) Top- down
approach emphasized on the vertical factors of a trophic structure, that the number of
trophic levels present under different conditions influence the pattern of biomass
partitioning among trophic levels. More specifically, top down approach viewed resource
limitation and predator limitation as having relatively exclusive roles, predicting that
biomass partitioning into trophic levels would depend on whether there were an even or
odd number of trophic levels. (Mathew et al 1997) Therefore, in order to accurately and
precisely examine how productivity and predation jointly affect trophic structure, a
theory that synthesizes these two views into one is desired in the ecological field.
Researchers today such as Power (1992) and Oksanen (1981) have attempted to
synthesize the above two theories into one. However, as of today, a relatively simple, yet
precise model is yet to be discovered by ecologists tomorrow. Discovery of such model
could clarify many unsolved mysteries in ecology such as the historical distribution of
species in specific systems. Furthermore, such a model will be very useful in predicting
species distributions and bio-manipulation experiment, thus help us better understand and
protect the environment. Therefore, working on such a model would certainly become an
exciting new area of ecology. [Another long paragraph – You need to work on how you
structure paragraphs.]
Literature Cited
Arditi R, Ginzburg LR. 1989. Coupling in predator-prey dynamics: ratio-dependence. J.
Theor. Biol. 139:311–26
Carpenter SR, Kitchell JF. 1984. Plankton community structure and limnetic primary
production. Am. Nat. 124:159–72
Elton C. 1927. Animal Ecology. London: Sidgwick & Jackson
Hairston NG, Smith FE, Slobodkin LB. 1960. Community structure, population control,
and competition. Am. Nat. 44:421–25
Hutchinson GE (1961) The paradox of the plankton. Am Nat 95:137–145 The American
Naturalist
Lindeman, R.L. 1942. The trophic-dynamic aspect of ecology. Ecology 23:399 – 418.
Mathew A. Leibold, Jonathan M. Chase, Jonathan B. Shurin, and and Amy L. Downing,
1997. SPECIES TURNOVER AND THE REGULATION OF TROPHIC
STRUCTURE. Annual Review of Ecology and Systematics. 28: 467-494
Meckler A N (2004) New organic matter degradation proxies: valid in lake systems?
Limnology and oceanography 49: 2023—2033. November
McQueen DJ, Post JR, Mills E. 1986. Trophic relationships in freshwater pelagic
ecosystems. Can. J. Fish. Aquat. Sci. 43:1571–1581
Oksanen L, Fretwell SD, Arrüda J, Miemela P. 1981. Exploitation ecosystems along
gradients of primary productivity. Am. Nat. 118:240–61
Power ME. 1992. Top-down and bottom-up forces in food webs: Do plants have primacy?
Ecology 73:733–746
Schindler DW, Armstrong FA, Holmgren SK, Brunkill GJ. 1971. Eutrophication of lake
227, Experimental Lakes Area, Northwest Ontario, by addition of phosphorus and
nitrates. J. Fish. Res. Board Can. 28:1763–82
Tilman D (1976) Ecological competition between algae: experimental confirmation of
resource-based competition theory. Science 192:463–465
Check your citation format. Some of your citations are fine but others leave off the year.
Overall a good paper. You focused on a few of the impacts of Lindeman’s study and
worked to trace them forward. Several places need some editing and rewording.
This report explains nicely the content of the Lindeman article, but does not do a
particularly good job of showing how subsequent literature was influenced by it. Instead,
there are somewhat tangential discussion of topics like top-down and bottom-up. You
need to integrate better so as to show how the field was and continues to be influenced by
Lindeman. The paper has been cited in excess of 650 times since 1980, so researchers
are reading and citing the work. Toward what end are they citing it?
16 B-